Method of producing wear resistant steel rails



Patented Nov. 27, 1951 UNITED STATES PATENT OFFICE METHOD OF PRODUCING WEAR RESISTANT STEEL RAILS Fritz Hofmann, Linz, Austria No Drawing. Application February 17, 1948, Serial No. 9,003

2 Claims. (01. 148-12.4)

1 2 This invention relates to the manufacture of The invention, therefore, is based on the mainsteel rails having a high degree of wear resistance. tenance of two cooling steps of which the one is Numerous processes have been developed to rapid cooling from the rolling temperature to achieve this important object. Most of these about between 620 to 660 C., and the second is prior art processes are based on a treatment of 5 represented by slow cooling from a critical temthe rails which consists of a succession and a perature to atmospheric temperatures.

variety of heating and cooling steps with the pur- The steel used for the production of the rails pose in view to secure optimum hardening condiin conformity with this invention should contain tions. .35 to 1.0% carbon, 1.3 to 2.0% manganese, and

In conformity with a known process of this type .5 to 1.5% silicon; the steel may additionally conthe rail is heated to a temperature of over 850 0., tain chromium, mo ybdenum, Vanadium and quenched to a temperature of about 500-700 C. other steel components within customary limits.

and then slowly cooled; a reheating step may be The invention will now be described more in introduced between the quenching and the slow detail.

cooling procedure, The rail is rolled from a steel containing .55% In accordance with a modification of this methcarbon, .75% silicon and 1.5% manganese, in

0d the rail is upon leaving the rolls quenched, readdition to normal percentages of sulphur and heated to about 730 c. and finally cooled at a pho phoru Th rail is rolled from the steel at slow rate. The method, therefore, includes the a temperature of between about 1050 to 1180 C. combination of at least three different tempera- As the rail leaves the rolls it is rapidly cooled ture steps. to a temperature of about 640 C. at which point In accordance with another prior art method the cooling is S we d by embedding the the rail is, as it comes from the rolls, directly and rail in sand until atmospheric temperature is rapidly cooled to a temperature between 550 to ea hed- 310 0., hereupon annealed at a temperature of What I claim is:

between 550 to 660 C. and then cooled. Also this 1. A method for producing a wear resistant method requires a succession of at least three steel rail compr the tep of ol ing he rail temperature treating steps. from a steel having 0.35 to 1.0 per cent carbon,

It has also been suggested to cool the rails on 1.3 to 2 per cent manganese and 0.5 to 1.5 per cent the hot bed below the critical temperature range silicon, rest iron at a t p a of about 1050 which is given to be between about 450 to 300 c. o 1l80 0., co lin the rail as it comes from the Hereupon the rail is slowly cooled in a closed vesrolling mill directly and p y until the a sel to about 50 C. and then exposed to air for the reaches a temperature f between 660 to 620 C. final cooling. and hereafter cooling the rail at a slower rate The characterizing feature of this method is the 5 than before until it reaches atmospheric quick cooling to a temperature below the critical peraturerange and the subdivision of the slow cooling pro- A method o producing a ear resistant cedure into separate steps. Also this method s l a l comprising the s s f ll n th ra l comprises three distinct temperature treating in a rolling mill m a ee avi 0.35 to 1.0 stages. per cent carbon, 1.3 to 2 per cent manganese and In conformity with still another method the 0.5 to 1.5 p r c t si st ir n a a t p rarail is heated to a temperature above the thermal e of about 1060 1180 quenching the ra critical range, quenched to a temperature of not directly p its emergence from e rolling l less than 250 C., reheated to below the thermal to a tempe a of about 660 t0 C! herecritical temperature and then slowly cooled to ft r olin the rail a a slower rate than beatmospheric temperatures. Also in this case fore y embedding the Sa e into Sand until it three different temperature treating steps are rereaches atmospheric temperaturequired. .FRI'IZ HOFMANN.

The invention utilizes the combination of a rapid and a slow cooling step, but it is based on REFERENCES CITED the recognition that the rapid cooling from the 60 The f I ollowing references are of record in the rooling temperature of the rails must be directly fil of this patent; carried-out in such a manner that a well defined hardening structure results; this aim is achieved UNITED STATES PATENTS by rapidly cooling the rail as it comes from the Number Name Date rolls to a temperature of about between 620 to 1,846,684 Kenney Feb. 23, 1932 660 C. 1 1,943,944 Whyte Jan. 16, 1934 Hereupon the rail is slowly cooled to atmos- 2,101,312 Gerhardt Dec. 7, 1937 pheric temperatures. 

1. A METHOD FOR PRODUCING A WEAR RESISTANT STEEL RAIL COMPRISING THE STEPS OF ROLLING THE RAIL FROM A STEEL HAVING 0.35 TO 1.0 PER CENT CARBON, 1.3 TO 2 PER CNET MANGANESE AND 0.5 TO 1.5 PER CENT SILICON, REST IRON AT A TEMPERATURE OF ABOUT 1050 TO 1180* C., COOLING THE RAIL AS IT COMES FROM THE ROLLING MILL DIRECTLY AND RAPIDLY UNTIL THE RAIL REACHES A TEMPERATURE OF BETWEEN 660 TO 620* C. AND HEREAFTER COOLING THE RAIL AT A LOWER RATE THAN BEFORE UNTIL IT REACHES ATMOSPHERIC TEMPERATURE. 